94 VETEEINAEY TOXICOLOGY 



rise sometimes to poisoning. In the South-Eastern United 

 States the Prunus caroliniana, laurel cherry, or mock orange, 

 which is cultivated as a hedge, and P. serotina, or wild 

 black cherry, an Eastern forest tree, both similarly have 

 proved dangerous. In South Africa Dichapetalum cymosum, 

 gift-blaar or poison leaf, is a most dangerous cyanogenetic 

 plant, having caused losses in the Transvaal, Bechuana- 

 land, and Ehodesia. J. T. Dumphy^ studied the effects on 

 sheep, and states that IJ ounces of the leaves is sometimes, 

 and 2 ounces always, fatal to them. They eat it if kept 

 starved, but once having been affected and recovered they 

 refuse it. 



In addition to the above mentioned, many of the 

 Leguminosce, in particular Phaseolus lunatus (Java or Ean- 

 goon bean, Haricot de Lime), and species of vetch {Vicia) ; 

 certain of the Graminece — e.g., the millet, or sorghum, and 

 the maize ; and, amongst the Linacece, common flax, Linum 

 usitatissimum and its varieties {L. catharticum, etc.) also 

 contain cyanogenetic glucosides, such as phaseolunatin (or 

 linamarin), which yields on fermentation 'glucose, acetone, 

 and hydrocyanic acid. 



The quantity of this glucoside, which is unevenly dis- 

 tributed throughout the whole of the plant, varies widely ; 

 thus it is present in sufficient quantity in the young millet 

 to cause poisoning, but is absent or in insufficient quantity 

 to prove dangerous in the mature plant. Losses of British 

 horses by the eating of young millet occurred in our first 

 Egyptian campaign. In the Phaseolus (or Java bean) the 

 percentage of glucoside in the wild East Indian varieties, 

 which vary in colour from pale reddish-brown to purple, 

 amounts to rather more than 0"1 per cent.® 



The white beans of the same species contain only about 

 one-tenth part of this proportion, and in the cultivated 

 varieties the proportion is very small, clearly pointing to 

 the fact that the production of the glucoside is a means 

 of natural defence. From the practical point of view only 

 the dark coloured, and especially the purple, beans are to 

 be regarded with suspicion. In 1906 considerable poisoning 



